Credit cards have become ubiquitous in consumer transactions. As is well known to those having skill in the art, a credit card employs a package, generally plastic, having standardized vertical and horizontal dimensions such as, for example, about 2⅛″ by about 3⅜″, and including first and second opposing faces. One face generally includes a logo, credit card number, expiration date and/or other indicia. The second face may include a signature block and a magnetic stripe.
Many individuals have a large number of credit cards that they carry in their wallet or purse. Unfortunately, given the limited size of the wallet or purse, it may be impractical for individuals to carry all of their credit cards. To eliminate some of the bulk, many companies have created keychain versions of their credit cards. However, the user of these credit cards may then carry a plethora of keychain credit cards, especially “club” cards, on a keychain along with their keys, so that there still may be limits on an individual's capacity to carry credit cards.
Electronic credit cards also have been proposed in an attempt to replace one or more conventional credit cards. See, for example, U.S. Pat. Nos. 5,825,353; 6,609,654; 6,732,919 and RE38,137, as well as U.S. Patent Application Publications U.S. 2003/0061157 and U.S. 2004/0117514. Attempts have been made to market electronic credit cards, as described, for example, at the websites PrivaSys.com and chameleonnetwork.com. Finally, Xircom has marketed the REX line of micro Personal Digital Assistants (PDA), which provide a credit card-sized PDA.